1. Field of the Invention
The present invention relates to a loudspeaker system.
2. Description of the Related Art
In the case where a human speaker and an audience are present within the same room having an area or space so large that the human speaker cannot make his/her own voice sufficiently heard by the audience, voice amplification is necessitated.
Conventionally, to carry out voice amplification, a human speaker has to utter voice at a location where a microphone is fixedly set, or otherwise has to carry a microphone, for collection of clear sound. Further, during a question-and-answer session or the like when people present make speeches in turns, each human speaker is required to move to the fixed microphone, or the microphone, not fixed, is required to be moved to the human speaker.
Further, a reproduction system, which is generally comprised of loudspeakers in a centralized arrangement or loudspeakers disposed on a ceiling in a dispersed arrangement, suffers from problems. In the case of the centralized arrangement, voice is amplified more than necessary in the vicinity of the loudspeakers, while in the case of the dispersed arrangement, voice is amplified more than necessary in the vicinity of the human speaker. In short, voice is not uniformly amplified within the same room.
Japanese Laid-Open Patent Publication (Kokai) No. H09-65470 discloses an acoustic system for a temple, for amplifying voice collected by a fixed microphone, using loudspeakers disposed on a ceiling in a dispersed arrangement, wherein the volumes of the respective loudspeakers are set such that they are progressively reduced toward the microphone, to thereby average the volumes of sounds synthesized from the natural voice and voices amplified by the respective loudspeakers.
As described hereinabove, in the conventional loudspeaker system, a human speaker has to speak at a location where a microphone is fixedly set, or otherwise has to carry a microphone, for collection of clear sound. Further, when a plurality of human speakers are present, each human speaker is required to move to the fixed microphone, or the microphone, not fixed, is required to be moved to each human speaker.
In the case where a wired microphone is to be moved, it is necessary to take care of a microphone cable, which troubles a human speaker a lot. On the other hand, as for a wireless microphone, the Radio Law provides that acquisition of a license or registration is required, and the consumer band suffers from the problems of interference and wiretapping (leakage of information).
Further, when a plurality of microphones are provided, it is necessary to manually switch between the microphones, and hence an operator or operators is/are needed from time to time. Furthermore, when a plurality of microphones are used, reduction of a loop gain per system makes it difficult to suppress howling and maintain voice clarity and sound quality.